90 research outputs found

    Mechanisms and Control of Self-Emulsification upon Freezing and Melting of Dispersed Alkane Drops

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    Emulsification requires drop breakage and creation of a large interfacial area between immiscible liquid phases. Usually, high-shear or high-pressure emulsification devices that generate heat and increase the emulsion temperature are used to obtain emulsions with micrometer and submicrometer droplets. Recently, we reported a new, efficient procedure of self-emulsification (Tcholakova et al. Nat. Commun. 2017, 8, 15012), which consists of one to several cycles of freezing and melting of predispersed alkane drops in a coarse oil-in-water emulsion. Within these freeze-thaw cycles of the dispersed drops, the latter burst spontaneously into hundreds and thousands of smaller droplets without using any mechanical agitation. Here, we clarify the main factors and mechanisms, which drive this self-emulsification process, by exploring systematically the effects of the oil and surfactant types, the cooling rate, and the initial drop size. We show that the typical size of the droplets, generated by this method, is controlled by the size of the structural domains formed in the cooling-freezing stage of the procedure. Depending on the leading mechanism, these could be the diameter of the fibers formed upon drop self-shaping or the size of the crystal domains formed at the moment of drop-freezing. Generally, surfactant tails that are 0-2 carbon atoms longer than the oil molecules are most appropriate to observe efficient self-emulsification. The specific requirements for the realization of different mechanisms are clarified and discussed. The relative efficiencies of the three different mechanisms, as a function of the droplet size and cooling procedure, are compared in controlled experiments to provide guidance for understanding and further optimization and scale-up of this self-emulsification process

    Funkcionalne osobine sojeva bakterija mlečne kiseline i mikrokoka u sredini sličnoj mesnoj masi sirovih kobasica kao modelu

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    In this study we investigated the potential probiotic properties of Lactobacillus plantarum L 24 - 2, Lactococcus lactis biovar diacetylactis N 237 and strain Micrococcus sp. It has been found that microbial species exhibited the ability to survive under conditions of high concentrations of bile salts (2.0%) and low pH (2.0). This ability varies for different types, but they will remain until the end of experiments zivotosposobne. This, together with the antimicrobial activity projavljenoj them makes them suitable for the new composition uklucivane the starter culture, which can be effectively used as an antimicrobial barrier to the development of pathogenic bacteria in the manufacture of a crude - product of dried meat.U ovom radu su ispitivana potencijalna probiotska svojstva bakterija Lactobacillus Plantarum soj L 24 - 2, Lactococcus lactis biovar diacetilactis soj N 237 i Micrococcus sp. Utvrđeno je da mikrobne vrste pokazuju sposobnost za preživljavanje pod uslovima visoke koncentracije žučnih soli (2,0%) i niskog pH (2.0). Ova sposobnost varira kod različitih ispitivanih bakterija, ali sve one ostaju životno sposobne do kraja eksperimenata. Ovo, zajedno sa dokazanom antimikrobnom aktivnošću čini ih pogodnim za uključivane u sastav novih starter kultura, koje mogu efikasno poslužiti kao antimikrobna barijera za razvoj patogenih bakterija u proizvodnji sirovih - sušenih proizvoda od mesa

    A destabilized bacterial luciferase for dynamic gene expression studies

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    Fusions of genetic regulatory elements with reporter genes have long been used as tools for monitoring gene expression and have become a major component in synthetic gene circuit implementation. A major limitation of many of these systems is the relatively long half-life of the reporter protein(s), which prevents monitoring both the initiation and the termination of transcription in real-time. Furthermore, when used as components in synthetic gene circuits, the long time constants associated with reporter protein decay may significantly degrade circuit performance. In this study, short half-life variants of LuxA and LuxB from Photorhabdus luminescens were constructed in Escherichia coli by inclusion of an 11-amino acid carboxy-terminal tag that is recognized by endogenous tail-specific proteases. Results indicated that the addition of the C-terminal tag affected the functional half-life of the holoenzyme when the tag was added to luxA or to both luxA and luxB, but modification of luxB alone did not have a significant effect. In addition, it was also found that alteration of the terminal three amino acid residues of the carboxy-terminal tag fused to LuxA generated variants with half-lives of intermediate length in a manner similar to that reported for GFP. This report is the first instance of the C-terminal tagging approach for the regulation of protein half-life to be applied to an enzyme or monomer of a multi-subunit enzyme complex and will extend the utility of the bacterial luciferase reporter genes for the monitoring of dynamic changes in gene expression

    Temporal changes in the epidemiology, management, and outcome from acute respiratory distress syndrome in European intensive care units: a comparison of two large cohorts

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    Background: Mortality rates for patients with ARDS remain high. We assessed temporal changes in the epidemiology and management of ARDS patients requiring invasive mechanical ventilation in European ICUs. We also investigated the association between ventilatory settings and outcome in these patients. Methods: This was a post hoc analysis of two cohorts of adult ICU patients admitted between May 1–15, 2002 (SOAP study, n = 3147), and May 8–18, 2012 (ICON audit, n = 4601 admitted to ICUs in the same 24 countries as the SOAP study). ARDS was defined retrospectively using the Berlin definitions. Values of tidal volume, PEEP, plateau pressure, and FiO2 corresponding to the most abnormal value of arterial PO2 were recorded prospectively every 24 h. In both studies, patients were followed for outcome until death, hospital discharge or for 60 days. Results: The frequency of ARDS requiring mechanical ventilation during the ICU stay was similar in SOAP and ICON (327[10.4%] vs. 494[10.7%], p = 0.793). The diagnosis of ARDS was established at a median of 3 (IQ: 1–7) days after admission in SOAP and 2 (1–6) days in ICON. Within 24 h of diagnosis, ARDS was mild in 244 (29.7%), moderate in 388 (47.3%), and severe in 189 (23.0%) patients. In patients with ARDS, tidal volumes were lower in the later (ICON) than in the earlier (SOAP) cohort. Plateau and driving pressures were also lower in ICON than in SOAP. ICU (134[41.1%] vs 179[36.9%]) and hospital (151[46.2%] vs 212[44.4%]) mortality rates in patients with ARDS were similar in SOAP and ICON. High plateau pressure (> 29 cmH2O) and driving pressure (> 14 cmH2O) on the first day of mechanical ventilation but not tidal volume (> 8 ml/kg predicted body weight [PBW]) were independently associated with a higher risk of in-hospital death. Conclusion: The frequency of and outcome from ARDS remained relatively stable between 2002 and 2012. Plateau pressure > 29 cmH2O and driving pressure > 14 cmH2O on the first day of mechanical ventilation but not tidal volume > 8 ml/kg PBW were independently associated with a higher risk of death. These data highlight the continued burden of ARDS and provide hypothesis-generating data for the design of future studies

    The clinical relevance of oliguria in the critically ill patient : Analysis of a large observational database

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    Funding Information: Marc Leone reports receiving consulting fees from Amomed and Aguettant; lecture fees from MSD, Pfizer, Octapharma, 3 M, Aspen, Orion; travel support from LFB; and grant support from PHRC IR and his institution. JLV is the Editor-in-Chief of Critical Care. The other authors declare that they have no relevant financial interests. Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Urine output is widely used as one of the criteria for the diagnosis and staging of acute renal failure, but few studies have specifically assessed the role of oliguria as a marker of acute renal failure or outcomes in general intensive care unit (ICU) patients. Using a large multinational database, we therefore evaluated the occurrence of oliguria (defined as a urine output 16 years) patients in the ICON audit who had a urine output measurement on the day of admission were included. To investigate the association between oliguria and mortality, we used a multilevel analysis. Results: Of the 8292 patients included, 2050 (24.7%) were oliguric during the first 24 h of admission. Patients with oliguria on admission who had at least one additional 24-h urine output recorded during their ICU stay (n = 1349) were divided into three groups: transient - oliguria resolved within 48 h after the admission day (n = 390 [28.9%]), prolonged - oliguria resolved > 48 h after the admission day (n = 141 [10.5%]), and permanent - oliguria persisting for the whole ICU stay or again present at the end of the ICU stay (n = 818 [60.6%]). ICU and hospital mortality rates were higher in patients with oliguria than in those without, except for patients with transient oliguria who had significantly lower mortality rates than non-oliguric patients. In multilevel analysis, the need for RRT was associated with a significantly higher risk of death (OR = 1.51 [95% CI 1.19-1.91], p = 0.001), but the presence of oliguria on admission was not (OR = 1.14 [95% CI 0.97-1.34], p = 0.103). Conclusions: Oliguria is common in ICU patients and may have a relatively benign nature if only transient. The duration of oliguria and need for RRT are associated with worse outcome.publishersversionPeer reviewe

    Evaluation of the combining ability of mutant maize lines

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    Abstract. The study shows the results of a preliminary evaluation of the combining ability for grain yield of 17 mutant maize lines. For the purpose the top cross method for early testing and the mathematical model of Savchenko for analysis of the general and the specific combining ability were used. The lines were tested on three testers with high general combining ability that belong to two genetic groups: K 46 52 and XM 552 from SSS and N 192 – Lancaster. For the purposes of evaluation of the productive abilities of the received top cross two preliminary varietal experiments were carried out at the experimental field of Maize Research Institute, Knezha As a result of the conducted experimental work and the analysis it was found that the highest general combining ability have lines XM 11 6 and XM 12 1. These lines can be included as components of high-yielding synthetics or as testers in analyzing crosses to determine general combining ability in early stages of the selection process. The above lines with high specific combining ability – XM 11 13 and XM 11 46 are suitable for inclusion in combinations to develop high-yielding hybrids. Three of the tested lines XM 11 7 11 XM 10 and XM 11 11 have both high GCA and SCA. These lines can be used in corresponding breeding in the selection programs

    Knezha 560 – a new mid-late maize hybrid

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    Abstract. Тhe article presents a short characteristic of morphological, biological and economic qualities of a new maize hybrid Knezha (Kn) 560. The hybrid is a single cross, from mid-late group – FAO 500-599. It is recognized in 2017 by the Expert Commission of Executive Agency of Variety Testing, Field Inspection and Seed Control (EAVTFISC). At the points of ecological variety trails (EVT) and EAVTFISC it was compared with the American hybrid PR 35 P 12 and the Bulgarian hybrid – Knezha 509. During the testing period in the experimental field of the Maize Research Institute (MRI) – town of Knezha, the three-year average grain yield of hybrid Knezha 560 exceeded the standard PR 35 Р 12 hybrid by 19.3% and Knezha 509 hybrid by 37.3%. In the EAVTFISC system, the new hybrid exceeds the middle standard by 0.8%. The hybrid is stress-tolerant and resistant to economically important diseases and pests of maize. With this high-yielding and competitive maize hybrid, the group of mid-late maize hybrids offered on the Bulgarian seed market is being filled

    Variation in the chemical composition and physical characteristics of grain from winter barley varieties

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    Abstract. The article presents the biological and morphological parameters of the new grain maize hybrid from middle early group. The hybrid is acknowledged in 2017, after three years of testing in the territorial station at Executive Agency of Variety Testing, Field Inspection and Seed Control (EAVTFISC) with standard American hybrid P 9494 and Knezha 435, a widespread Bulgarian hybrid. During the period of testing under conditions without irrigation in the experimental field of the Maize Research Institute – town of Knezha the three years average of the new hybrid exceeded the standard P 9494 by 7.4%, and Knezha 435 by 8.6%. In the ecological network of the country in 2011, under conditions without irrigation, the hybrid produced grain yield 2.6% above the foreign and 4.7% above the Bulgarian standard. In 2016 at EAVTFISC the Knezha 461 maize hybrid exceeded by average grain yield the P9494 standard by 1.5%. The testing was conducted at four points under non-irrigated conditions. The moisture content in the harvesting time is near to that of P9494 and lower than the moisture of Knezha 435. The new high-yielding and competitive hybrid Knezha 461 supplies deficiencies in the middle early group of Bulgarian hybrids, where the foreign ones take prevalence

    Use of recurrent selection of early flowering in late maize synthetic population. Results of second cycle of breeding

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    Abstract. During the period 2012 – 2014, a second cycle of recurrent selection of early flowering in a synthetic maize population “Exotic-07” was conducted 2 and finished on the experimental field of Maize Research institute – Knezha. The experiments are carried out by a block method, on a test plot of 10 m , with three replications, and the respective for the region agricultural equipment. Twenty-three progeny from the first and second cycle, the source and improved exotic maize populations, as well as their testcrosses with the lines ХМ 4416 and PAU 1617 are tested. A phenotypic cycle assumes a leading position in terms of dates of plant silking as the forms of the earliest flowering are used as pollen in the population. The selected early flowering forms are sown for inbreeding and forming an improved maize population. As a direct result of the work of improvement, progeny with a period of days until silking averagely shorter with 5 days and grain moisture lowered by 1.1% are obtained. The aim of this study is to point out inbred lines with a shorter vegetative period and use them as parental forms for obtaining high-yielding mid-late maize hybrids
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